Fairy Bloom Freesia

I had got all the rest of the achievements 49/50.I only have left the endless waltz but for somekind of reason, it doesn't pop up, neither on the game or steam; i have bounce with ether saber 2 like 7-8 times an enemy, both on training or a stage on story mode, and still doesn't get the achievementPlease help, i'm an achievement hunter and i hate when this happens